/* GIMP - The GNU Image Manipulation Program
 * Copyright (C) 1995 Spencer Kimball and Peter Mattis
 *
 * file-gegl.c -- GEGL based file format plug-in
 * Copyright (C) 2012 Simon Budig <simon@gimp.org>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

#include "config.h"

#include <stdlib.h>
#include <errno.h>

#include <glib/gstdio.h>

#include <libgimp/gimp.h>
#include <libgimp/gimpui.h>

#include "libgimp/stdplugins-intl.h"


#define PLUG_IN_BINARY "file-gegl"


typedef struct _FileFormat FileFormat;

struct _FileFormat
{
  const gchar *file_type;
  const gchar *mime_type;
  const gchar *extensions;
  const gchar *magic;

  const gchar *load_proc;
  const gchar *load_blurb;
  const gchar *load_help;
  const gchar *load_op;

  const gchar *save_proc;
  const gchar *save_blurb;
  const gchar *save_help;
  const gchar *save_op;
};


static void     query      (void);
static void     run        (const gchar      *name,
                            gint              nparams,
                            const GimpParam  *param,
                            gint             *nreturn_vals,
                            GimpParam       **return_vals);
static gint32   load_image (const gchar      *filename,
                            const gchar      *gegl_op,
                            GError          **error);
static gboolean save_image (const gchar      *filename,
                            const gchar      *gegl_op,
                            gint32            image_ID,
                            gint32            drawable_ID,
                            GError          **error);


static const FileFormat file_formats[] =
{
  {
    N_("Radiance RGBE"),
    "image/vnd.radiance",
    "hdr",
    "0,string,#?",

    "file-load-rgbe",
    "Load files in the RGBE file format",
    "This procedure loads images in the RGBE format, using gegl:rgbe-load",
    "gegl:rgbe-load",

    "file-save-rgbe",
    "Saves files in the RGBE file format",
    "This procedure exports images in the RGBE format, using gegl:rgbe-save",
    "gegl:rgbe-save",
  },
  {
    N_("OpenEXR image"),
    "image/x-exr",
    "exr",
    "0,lelong,20000630",

    /* no EXR loading (implemented in native GIMP plug-in) */
    NULL, NULL, NULL, NULL,

    "file-exr-save",
    "Saves files in the OpenEXR file format",
    "This procedure saves images in the OpenEXR format, using gegl:exr-save",
    "gegl:exr-save"
  }
};


const GimpPlugInInfo PLUG_IN_INFO =
{
  NULL,  /* init_proc */
  NULL,  /* quit_proc */
  query, /* query proc */
  run,   /* run_proc */
};

MAIN ()

static void
query (void)
{
  static const GimpParamDef load_args[] =
  {
    { GIMP_PDB_INT32,  "run-mode",     "The run mode { RUN-INTERACTIVE (0), RUN-NONINTERACTIVE (1) }" },
    { GIMP_PDB_STRING, "filename",     "The name of the file to load." },
    { GIMP_PDB_STRING, "raw-filename", "The name entered" },
  };

  static const GimpParamDef load_return_vals[] =
  {
    { GIMP_PDB_IMAGE,  "image",        "Output image" }
  };

  static const GimpParamDef save_args[] =
  {
    { GIMP_PDB_INT32,    "run-mode",     "The run mode { RUN-INTERACTIVE (0), RUN-NONINTERACTIVE (1) }" },
    { GIMP_PDB_IMAGE,    "image",        "Input image" },
    { GIMP_PDB_DRAWABLE, "drawable",     "Drawable to save" },
    { GIMP_PDB_STRING,   "filename",     "The name of the file to save the image in" },
    { GIMP_PDB_STRING,   "raw-filename", "The name of the file to save the image in" }
  };

  gint i;

  for (i = 0; i < G_N_ELEMENTS (file_formats); i++)
    {
      const FileFormat *format = &file_formats[i];

      if (format->load_proc)
        {
          gimp_install_procedure (format->load_proc,
                                  format->load_blurb,
                                  format->load_help,
                                  "Simon Budig",
                                  "Simon Budig",
                                  "2012",
                                  format->file_type,
                                  NULL,
                                  GIMP_PLUGIN,
                                  G_N_ELEMENTS (load_args),
                                  G_N_ELEMENTS (load_return_vals),
                                  load_args, load_return_vals);

          gimp_register_file_handler_mime (format->load_proc,
                                           format->mime_type);
          gimp_register_magic_load_handler (format->load_proc,
                                            format->extensions,
                                            "",
                                            format->magic);
        }

      if (format->save_proc)
        {
          gimp_install_procedure (format->save_proc,
                                  format->save_blurb,
                                  format->save_help,
                                  "Simon Budig",
                                  "Simon Budig",
                                  "2012",
                                  format->file_type,
                                  "*",
                                  GIMP_PLUGIN,
                                  G_N_ELEMENTS (save_args), 0,
                                  save_args, NULL);

          gimp_register_file_handler_mime (format->save_proc,
                                           format->mime_type);
          gimp_register_save_handler (format->save_proc,
                                      format->extensions, "");
        }
    }
}

static void
run (const gchar      *name,
     gint              nparams,
     const GimpParam  *param,
     gint             *nreturn_vals,
     GimpParam       **return_vals)
{
  static GimpParam   values[2];
  GimpPDBStatusType  status = GIMP_PDB_SUCCESS;
  GimpRunMode        run_mode;
  gint               image_ID;
  gint               drawable_ID;
  GError            *error = NULL;
  gint               i;

  INIT_I18N ();
  gegl_init (NULL, NULL);

  run_mode = param[0].data.d_int32;

  *nreturn_vals = 1;
  *return_vals  = values;

  values[0].type          = GIMP_PDB_STATUS;
  values[0].data.d_status = GIMP_PDB_EXECUTION_ERROR;

  for (i = 0; i < G_N_ELEMENTS (file_formats); i++)
    {
      const FileFormat *format = &file_formats[i];

      if (format->load_proc && !strcmp (name, format->load_proc))
        {
          image_ID = load_image (param[1].data.d_string, format->load_op, &error);

          if (image_ID != -1)
            {
              *nreturn_vals = 2;
              values[1].type         = GIMP_PDB_IMAGE;
              values[1].data.d_image = image_ID;
            }
          else
            {
              status = GIMP_PDB_EXECUTION_ERROR;
            }

          break;
        }
      else if (format->save_proc && !strcmp (name, format->save_proc))
        {
          GimpExportReturn export = GIMP_EXPORT_CANCEL;

          image_ID    = param[1].data.d_int32;
          drawable_ID = param[2].data.d_int32;

          /*  eventually export the image */
          switch (run_mode)
            {
            case GIMP_RUN_INTERACTIVE:
            case GIMP_RUN_WITH_LAST_VALS:
              gimp_ui_init (PLUG_IN_BINARY, FALSE);

              export = gimp_export_image (&image_ID, &drawable_ID, "GEGL",
                                          GIMP_EXPORT_CAN_HANDLE_RGB     |
                                          GIMP_EXPORT_CAN_HANDLE_GRAY    |
                                          GIMP_EXPORT_CAN_HANDLE_INDEXED |
                                          GIMP_EXPORT_CAN_HANDLE_ALPHA);

              if (export == GIMP_EXPORT_CANCEL)
                {
                  *nreturn_vals = 1;
                  values[0].data.d_status = GIMP_PDB_CANCEL;
                  return;
                }
              break;

            default:
              break;
            }

          if (! save_image (param[3].data.d_string,
                            format->save_op,
                            image_ID, drawable_ID,
                            &error))
            {
              status = GIMP_PDB_EXECUTION_ERROR;
            }

          if (export == GIMP_EXPORT_EXPORT)
            gimp_image_delete (image_ID);

          break;
        }
    }

  if (i == G_N_ELEMENTS (file_formats))
    status = GIMP_PDB_CALLING_ERROR;

  if (status != GIMP_PDB_SUCCESS && error)
    {
      *nreturn_vals = 2;
      values[1].type           = GIMP_PDB_STRING;
      values[1].data.d_string  = error->message;
    }

  values[0].data.d_status = status;

  gegl_exit ();
}

static gint32
load_image (const gchar  *filename,
            const gchar  *gegl_op,
            GError      **error)
{
  gint32             image_ID = -1;
  gint32             layer_ID;
  GimpImageType      image_type;
  GimpImageBaseType  base_type;
  GimpPrecision      precision;
  gint               width;
  gint               height;
  GeglNode          *graph;
  GeglNode          *sink;
  GeglNode          *source;
  GeglBuffer        *src_buf  = NULL;
  GeglBuffer        *dest_buf = NULL;
  const Babl        *format;

  gimp_progress_init_printf (_("Opening '%s'"),
                             gimp_filename_to_utf8 (filename));

  graph = gegl_node_new ();

  source = gegl_node_new_child (graph,
                                "operation", gegl_op,
                                "path",      filename,
                                NULL);
  sink = gegl_node_new_child (graph,
                              "operation", "gegl:buffer-sink",
                              "buffer",    &src_buf,
                              NULL);

  gegl_node_connect_to (source, "output",
                        sink,   "input");

  gegl_node_process (sink);

  g_object_unref (graph);

  if (! src_buf)
    {
      g_set_error (error, G_FILE_ERROR, G_FILE_ERROR_FAILED,
                   _("Could not open '%s'"),
                   gimp_filename_to_utf8 (filename));
      return -1;
    }

  gimp_progress_update (0.33);

  width  = gegl_buffer_get_width (src_buf);
  height = gegl_buffer_get_height (src_buf);
  format = gegl_buffer_get_format (src_buf);

  if (babl_format_is_palette (format))
    {
      base_type = GIMP_INDEXED;

      if (babl_format_has_alpha (format))
        image_type = GIMP_INDEXEDA_IMAGE;
      else
        image_type = GIMP_INDEXED_IMAGE;

      precision = GIMP_PRECISION_U8_GAMMA;
    }
  else
    {
      const Babl *model  = babl_format_get_model (format);
      const Babl *type   = babl_format_get_type (format, 0);
      gboolean    linear = TRUE;

      if (model == babl_model ("Y")  ||
          model == babl_model ("Y'") ||
          model == babl_model ("YA") ||
          model == babl_model ("Y'A"))
        {
          base_type = GIMP_GRAY;

          if (babl_format_has_alpha (format))
            image_type = GIMP_GRAYA_IMAGE;
          else
            image_type = GIMP_GRAY_IMAGE;

          if (model == babl_model ("Y'") ||
              model == babl_model ("Y'A"))
            linear = FALSE;
        }
      else
        {
          base_type = GIMP_RGB;

          if (babl_format_has_alpha (format))
            image_type = GIMP_RGBA_IMAGE;
          else
            image_type = GIMP_RGB_IMAGE;

          if (model == babl_model ("R'G'B'") ||
              model == babl_model ("R'G'B'A"))
            linear = FALSE;
        }

      if (linear)
        {
          if (type == babl_type ("u8"))
            precision = GIMP_PRECISION_U8_LINEAR;
          else if (type == babl_type ("u16"))
            precision = GIMP_PRECISION_U16_LINEAR;
          else if (type == babl_type ("u32"))
            precision = GIMP_PRECISION_U32_LINEAR;
          else if (type == babl_type ("half"))
            precision = GIMP_PRECISION_HALF_LINEAR;
          else
            precision = GIMP_PRECISION_FLOAT_LINEAR;
        }
      else
        {
          if (type == babl_type ("u8"))
            precision = GIMP_PRECISION_U8_GAMMA;
          else if (type == babl_type ("u16"))
            precision = GIMP_PRECISION_U16_GAMMA;
          else if (type == babl_type ("u32"))
            precision = GIMP_PRECISION_U32_GAMMA;
          else if (type == babl_type ("half"))
            precision = GIMP_PRECISION_HALF_GAMMA;
          else
            precision = GIMP_PRECISION_FLOAT_GAMMA;
        }
    }


  image_ID = gimp_image_new_with_precision (width, height,
                                            base_type, precision);
  gimp_image_set_filename (image_ID, filename);

  layer_ID = gimp_layer_new (image_ID,
                             _("Background"),
                             width, height,
                             image_type,
                             100,
                             gimp_image_get_default_new_layer_mode (image_ID));
  gimp_image_insert_layer (image_ID, layer_ID, -1, 0);
  dest_buf = gimp_drawable_get_buffer (layer_ID);

  gimp_progress_update (0.66);

  gegl_buffer_copy (src_buf, NULL, GEGL_ABYSS_NONE, dest_buf, NULL);

  g_object_unref (src_buf);
  g_object_unref (dest_buf);

  gimp_progress_update (1.0);

  return image_ID;
}

static gboolean
save_image (const gchar  *filename,
            const gchar  *gegl_op,
            gint32        image_ID,
            gint32        drawable_ID,
            GError      **error)
{
  GeglNode   *graph;
  GeglNode   *source;
  GeglNode   *sink;
  GeglBuffer *src_buf;

  src_buf = gimp_drawable_get_buffer (drawable_ID);

  graph = gegl_node_new ();

  source = gegl_node_new_child (graph,
                                "operation", "gegl:buffer-source",
                                "buffer",    src_buf,
                                NULL);
  sink = gegl_node_new_child (graph,
                              "operation", gegl_op,
                              "path",      filename,
                              NULL);

  gegl_node_connect_to (source, "output",
                        sink,   "input");

  gegl_node_process (sink);

  g_object_unref (graph);
  g_object_unref (src_buf);

  return TRUE;
}